This video will focus on troubleshooting the reversing valve on a heat pump, also known as the switchover valve. The reversing valve exists to change the direction of the refrigerant. Here are some tips for what we should be troubleshooting to diagnose or a heat pump not heating.

In heating mode, a reversing valve reverses the refrigerant flow to make the evaporator coil inside the hot condenser coil and the outdoor condenser coil the cold evaporator coil. So, we're trying to extract heat from the outside and bring it inside.

The reversing valve exists to change the direction of the refrigerant. Twentyfour volts from the defrost board energizes the solenoid on it. On 90% of the systems out there, the reversing valve defaults to heating mode. This way, if the valve is not working or doesn't have 24 volts flowing to it, at least the heat still works. That's because, in most parts of the country, heating is more important than cooling.

The solenoid coil moves a pilot valve that creates a pressure difference inside the reversing valve. Small capillarytype tubes house the pressurized refrigerant and push the slide laterally to isolate two of the three holes leaving the reversing valve.

The tube in the middle and the tube coming in from the top are attached to the compressor. The incoming line is always the compressor's discharge line, and the middle tube of the three on the bottom is always the compressor's suction line.

The tubes where the refrigerant is flowing in different directions, whether in heating or cooling mode, are on the two sides of that middle suction line. One leads to the outdoor coil, and one leads to the indoor coil.